Nearly any plant material can be broken down into simple sugars.

Biofuel production focuses on taking the carbon that's already present in plants and converting it into burnable carbon-based fuels. Most of the carbon in a plant comes in the form of sugars, which can be readily converted into ethanol and less readily modified into other fuels.

Sugar is relatively easy to obtain from things like fruit and seeds, but those are also the sorts of things we like to eat. Most of the sugar in the rest of a plant, however, is locked into a complex polymer called cellulose. Figuring out a way to easily break down cellulose has been one of the major hurdles to the expansion of biofuels.

Now, researchers from the University of Wisconsin–Madison have figured out a chemical treatment that, given a bit of time, can completely dissolve any plant matter including wood. The end result is a solution containing mostly sugars, along with a few other organic molecules—some of which can be shunted off to synthesize the key ingredient of the chemical treatment itself.

The key ingredient in the chemical treatment is gamma-valerolactone, a ring-shaped molecule that incorporates an oxygen in its ring. On its own, this seems to be able to loosen up the cellulose and make it more accessible for chemical reactions. But it doesn't break it down into the individual sugars it's composed of. To do that, the researchers had to add some dilute sulfuric acid along with a bit of water (20 percent of the final solution) to keep everything in solution.

Essentially, that mixture gets sent into a heated reaction chamber stuffed with any kind of plant matter—the authors tested corn stalks after the corn had been harvested, as well as poplar and maple. If the solution is allowed to flow slowly through the reaction chamber, then it will completely break the plant material down into a mixture of sugars. The only solid material that's left is a small bit of particulate debris.

When the resulting sugar-rich solution comes out of the far end of the chamber, mixing it with a solution of table salt is enough to extract almost all of the sugar into a water solution. That solution can then be fed to yeast, which will convert it to ethanol. The remaining organic compounds stay in the organic phase. The gamma-valerolactone can then be pulled out of the organic solution and reused; the rest can be used as a chemical feedstock for other reactions—including the synthesis of gamma-valerolactone.

The researchers also found that they could speed up the reaction a bit, use a somewhat lower heat, and still extract a lot of sugar. The remaining plant matter can just be left in the reaction chamber when more material is added; if it wasn't broken down the first time, it's likely to be on the second pass.

The conversion into ethanol currently requires a fairly high degree of purification, but the authors are working on evolving a strain of yeast that operates efficiently in the solution as it comes out of the reactor. If that works out, then it will raise the efficiency of the process as a whole a bit.

And that's rather important, since they estimate that the ethanol produced by this process will be competitive as a fuel at a cost of just under $5.00. That's competitive with the enzymatic breakdown of plant material, which also liberates sugar for ethanol production. And, as noted above, neither of these processes competes with crops—in fact, they can use some of the byproducts of crops.

But right now, neither of those processes is competitive with either fossil fuels or ethanol produced from the crops themselves. So either of these technologies needs one of a few things: a big jump in efficiency, increases in the price of fossil fuels, policy decisions that limit the use of fossil fuels, or policy decisions that limit the amount of crops diverted into fuel production.

I would have liked a short description of how this compares to the current enzyme-based biofuel production (in terms of both efficiency and economy). Please consider that in the next follow-up article.

It's nice to see that we as a species are finally realizing that energy is all around us and doesn't have to be baked into crude oil in the earth's crust to be useful to us. I forget the story but I remember reading about an olive processing facility that began burning olive waste (pits, other organic material) and not only saved on hauling away the organic material, but also generated most of the plant's electricity from burning the organic byproducts.

It sounds like the above process could really work on any sort of organic material. Hopefully in the future we'll be able to turn organic byproducts that are now called waste into fuel.

This article would seem to imply they are using "waste" material from crops. There are very few things in modern agriculture that aren't already being used one way or the other. Corn and grain stalks are routinely used for hay and other feed bases. What isn't collected for say, vegetable crops, is plowed back into the soil to help the next year's plants grow.

This is a GREAT technology, but let's not think that there is all this waste material just going to rot or something. Making biofuel with crop plant material will be taking that material from some other process or product. As this works with wood too, perhaps the lumber industry would be a good place to look as the branches stripped from trees before transport tend to be gathered and burned if they aren't chipped on site.

It sounds like the gamma-valerolactone acts more as a catalyst than a reactant. Does all of it survive the process, or is some consumed as part of it (or broken down by the heat in the reaction chamber)?

Nothing. The soil loses a little bit more each year. But don't worry that won't become a huge world problem until your grand kids are middle aged. Live for the moment

"Resources exist to be consumed. And consumed they will be, if not by this generation then by some future. By what right does this forgotten future seek to deny us our birthright? None I say! Let us take what is ours, chew and eat our fill."

And, as noted above, neither of these processes competes with crops—in fact, they can use some of the byproducts of crops.

I was never comfortable with policies that divert food crops into fuel production. Fuel is not the first-best use of those resources by a long shot.

Whenever I see one of those "Powered by Bio-diesel" signs on a truck of bus, I imagine it saying "Powered by world hunger."

As mentioned above, even the by-products of crops already have uses, so diverting them still costs something. But I imagine those byproducts are easier to substitute than food itself, so the market will work out what gets used for what. Limbs and leaves left over by logging sound like an excellent place to start.

This process is barely out of the invention stage and Ars readers are ready to toss it in the great compost heap of failure.

Yes, right now it's too expensive to compete with relatively cheap fossil fuels. That price difference may not last forever. It is barely competitive with enzymatic processes according to the article. Let the best process win.

Yes, it could compete with other uses of cellulose material, such as animal fodder and soil amendments. Note however that every year there are millions of tons of cellulose waste landfilled or burned that could be diverted to ethanol production that would have no negative impact on agriculture at all. Additionally, cellulose crops can be grown on land that isn't suitable for more food crops and they can be grown more sustainably to boot.

Someday we will all drive cars powered by unicorn poots. This is a technology that uses existing infrastructure, doesn't require any breakthroughs in auto technology, is carbon neutral, and may buy us the time to breed up the vast herds of unicorns needed.

And, as noted above, neither of these processes competes with crops—in fact, they can use some of the byproducts of crops.

I was never comfortable with policies that divert food crops into fuel production. Fuel is not the first-best use of those resources by a long shot.

Whenever I see one of those "Powered by Bio-diesel" signs on a truck of bus, I imagine it saying "Powered by world hunger."

As mentioned above, even the by-products of crops already have uses, so diverting them still costs something. But I imagine those byproducts are easier to substitute than food itself, so the market will work out what gets used for what. Limbs and leaves left over by logging sound like an excellent place to start.

We make enough food to feed the world. It just doesn't get distributed efficiently. And we could make more food if wanted to.

In other words, not eating your broccoli doesn't contribute to starving a family on the other side of the world. (If we want to help them, we need to help them grow food over there, not ship them unwanted broccoli across the ocean. In most cases they could grow food, but they lack the infrastructure to do it efficiently.) Using food crops for fuel does make food more expensive. But rising fuel costs also makes food more expensive.

As we deplete our resources of energy that came from the sun long ago, we're going to have to use energy that came from the sun recently. We need to do that as efficiently as possible and it doesn't matter whether the path to energy goes through an edible product or not.

Whenever I see one of those "Powered by Bio-diesel" signs on a truck of bus, I imagine it saying "Powered by world hunger."

It's hardly fair to imply that biodiesel is "causing" world hunger. As mentioned in other comments above, the creation of *ANY* resource can have knockon effects that divert feedstocks from other pathways.

You might as well look at your own computer monitor and think "Powered by world hunger".

What "causes" world hunger is a world with 7 billion people, all trying to live well beyond what the Earth's natural resources and our level of technology can sustainably support (including a small percentage of those 7B living waaay above the rest).

If you ignore the "runs off agricultural waste that is currently used for other stuff" part, this is a great tech. You can grow weeds on marginal soil that isn't currently suited for anything. You can turn food waste into fuel. You can turn dissidents into fuel. Particulate pollution seems like a mostly-solved problem (air in most north american cities is very clean, despite continuously-increasing automotive use), and a close-to-cheap ($5.00/gal is cheaper than gas is here in Canada, and way cheaper than it is in Europe) biofuel solution would eliminate the carbon dioxide problem for many liquid fuels.

And since the other poster primed me to think of SMAC...

Quote:

It is every citizen's final duty to go into the tanks andbecome one with all the people.

The conversion into ethanol currently requires a fairly high degree of purification, but the authors are working on evolving a strain of yeast that operates efficiently in the solution as it comes out of the reactor. If that works out, then it will raise the efficiency of the process as a whole a bit.

Cost aside, what is the ratio of energy out to energy in, after all the bio material is grown, collected, and processed? And how does that ratio compare to current fossil fuels? This is I think, the better question with biofuels, because if your ratio in the process is not significantly greater than 1 then you can't gain any real economy from the process.

When the resulting sugar-rich solution comes out of the far end of the chamber, mixing it with a solution of table salt is enough to extract almost all of the sugar into a water solution. That solution can then be fed to yeast, which will convert it to ethanol. The remaining organic compounds stay in the organic phase. The gamma-valerolactone can then be pulled out of the organic solution and reused…

I work directly in this field (research in biomass processing for fuels). I've come to accept that it's part of the jargon, but this use of "organic phase" still irks me.

The water-soluble carbohydrates in the aqueous phase are "organic", just as "organic" as the carbon-containing molecules in the insoluble ("oil") phase.

But I assume John's use is just following J. S. Luterbacher et al. (haven't had time to read the Full Text yet)

ggeezz and ScottHW, no one thinks the corn for biofuel is snatched off the plate of some kid in a charity commercial... but the advent of diversion to biofuel has coincided with a reversal of long-term declines in global food prices despite record harvests. Food prices are still below, say, 1975 levels, but the dramatic rise from lows around 2000 is destabilizing in many parts of the world.

Saying that there is enough food in a tonnage sense ignores how real markets work. Diversion "here" increases prices "there" even if there ought to be enough for everybody.

This is some pretty neat tech, but wouldn't it be more efficient to skip a step and capture the solar energy ourselves, rather than letting plants do it? I mean, how much ethanol can an acre of corn waste (or grass, or whatever other plant material you are using) compare to the energy output of an acre of 20% efficient solar panels?

This is some pretty neat tech, but wouldn't it be more efficient to skip a step and capture the solar energy ourselves, rather than letting plants do it? I mean, how much ethanol can an acre of corn waste (or grass, or whatever other plant material you are using) compare to the energy output of an acre of 20% efficient solar panels?

The trouble is portable fuel. Batteries and fuel cells just don't have the energy density (energy per unit mass) of liquid fuels. So for the foreseeable future we need long haul trucks and airplanes driving on liquids if not necessarily your commuter car.

Yes, it could compete with other uses of cellulose material, such as animal fodder and soil amendments. Note however that every year there are millions of tons of cellulose waste landfilled or burned that could be diverted to ethanol production that would have no negative impact on agriculture at all. Additionally, cellulose crops can be grown on land that isn't suitable for more food crops and they can be grown more sustainably to boot.

IIRC, we've heard at least part of this story before, about switchgrass being farmed, then broken down into ethanol; as plans matured, one of the big problems turned out to be old-fashioned logistics: how do you get the harvested switchgrass to the fermentation plant without consuming all of the energy that you ultimately derive from the switchgrass? Again IIRC, this turned out to be a highly non-trivial problem. How do we solve that problem this time? I'm not saying that it can't be solved, but that it must be solved one way or another. Devil in the details, etc...

This technology is interesting but undoubtedly will not be the final word in converting biomass to fuel.

These scientists are trying to get nature to do something that the biological world has evolved to prevent from happening: the rapid degradation of plant material.

We can argue all day about the "true" cost of biofuel production, adding in the cost of transportation, planting and watering the crops, etc. And the depletion of soil biomass is of potential concern.

But in the big picture of things, all this comes from the sun. Plants use sunlight to convert carbon dioxide to cellulose; we will convert it to readily usable biofuel and burn it to extract this sunlight-sourced energy and release CO2 in the process. Using oil does the same thing, but with a few million years of delay from growing plant to extraction of energy.

I forget the story but I remember reading about an olive processing facility that began burning olive waste (pits, other organic material) and not only saved on hauling away the organic material, but also generated most of the plant's electricity from burning the organic byproducts.

Since installing a full-scale sized system in 2010, Musco has been able to treat its wastewater and generate 500 kwh/hr, or half of the plant's electrical needs for operations such as sorters, canners, pitting, packing, and labeling machines.

Quote:

Olive pits have an energy rating of 8,800 Btu per pound, higher than hard wood, and have a similar moisture level. The full-sized system currently in use at the Musco plant burns two to three tons of olive pits every hour.

Pits can be burned straight out of the plant, and there’s an easy screw feed system to get them fired in the combustion unit at a constant rate,” explains Frank Schubert, creator of the Bio-Reactor Burner (BRB) and RENEWS at CST.

At first I thought "This sounds like the least efficient thing ever!!" Then, I considered that we are currently drilling a couple miles into the Earth's crust to extract fossil fuels and then ship it to the mainland all while hoping we don't blow up or spill everything and wipe out an entire ecosystem. (Don't even get me started about fracking) So now this sounds promising!

At first I thought "This sounds like the least efficient thing ever!!" Then, I considered that we are currently drilling a couple miles into the Earth's crust to extract fossil fuels and then ship it to the mainland all while hoping we don't blow up or spill everything and wipe out an entire ecosystem. (Don't even get me started about fracking) So now this sounds promising!

You joke, but imagine using this process to extract flavoring compounds from bourbon barrels, while depolymerizing the cellulose to fermentable sugar.Obviously an expensive way to produce whiskey, and arguable whether it would be faster (barrel-aging time vs. time required for the new process), but might be a worthwhile method for producing flavoring extracts (either bourbon or vanilla flavored, although I think a good bit of "artificial" vanilla flavoring is derived from lignin already).

I'm beginning to think that all of evolutionary history is nothing more than a quest to digest cellulose efficiently.

Actually I have always been puzzled at the reason why cellulose digestion is not widespread in the animal world.Herbivores are mostly still using host to digest cellulose, and do so not very efficiently (therefore the "invention" of rumen etc...). Cellulose has been around and widespread for millions of years. Has this molecule invented the ultimate shield against digestion ? As I am not a biologist and not really a chemist, I don't know the answer.

When the resulting sugar-rich solution comes out of the far end of the chamber, mixing it with a solution of table salt is enough to extract almost all of the sugar into a water solution. That solution can then be fed to yeast, which will convert it to ethanol. The remaining organic compounds stay in the organic phase. The gamma-valerolactone can then be pulled out of the organic solution and reused…

I work directly in this field (research in biomass processing for fuels). I've come to accept that it's part of the jargon, but this use of "organic phase" still irks me.

The water-soluble carbohydrates in the aqueous phase are "organic", just as "organic" as the carbon-containing molecules in the insoluble ("oil") phase.

But I assume John's use is just following J. S. Luterbacher et al. (haven't had time to read the Full Text yet)

I'm confused, is "organic" in this use referring to the solvent, or what's in the solvent? The former is standard, the latter is not.

ggeezz and ScottHW, no one thinks the corn for biofuel is snatched off the plate of some kid in a charity commercial... but the advent of diversion to biofuel has coincided with a reversal of long-term declines in global food prices despite record harvests. Food prices are still below, say, 1975 levels, but the dramatic rise from lows around 2000 is destabilizing in many parts of the world.

Saying that there is enough food in a tonnage sense ignores how real markets work. Diversion "here" increases prices "there" even if there ought to be enough for everybody.

Correlation does not equal causation.

Fuel prices make up a significant percentage of food prices. The early 2000's saw a significant rise in the price of fuel. How much of that rise in food prices was due to biofuel and how much of it was due to just fuel?

IMO, it'd be more accurate to blame instability in the Middle East than biofuel. When you take a large portion of oil off the market and divert substantial resources to blowing things up it causes everything to be more expensive.

When the resulting sugar-rich solution comes out of the far end of the chamber, mixing it with a solution of table salt is enough to extract almost all of the sugar into a water solution. That solution can then be fed to yeast, which will convert it to ethanol. The remaining organic compounds stay in the organic phase. The gamma-valerolactone can then be pulled out of the organic solution and reused…

I work directly in this field (research in biomass processing for fuels). I've come to accept that it's part of the jargon, but this use of "organic phase" still irks me.

The water-soluble carbohydrates in the aqueous phase are "organic", just as "organic" as the carbon-containing molecules in the insoluble ("oil") phase.

But I assume John's use is just following J. S. Luterbacher et al. (haven't had time to read the Full Text yet)

Yes, but isn't it generally assumed in doing separation science that "aqueous phase" and "organic phase" are named for the solvent, and not the myriad other components in a mixture?

This is some pretty neat tech, but wouldn't it be more efficient to skip a step and capture the solar energy ourselves, rather than letting plants do it? I mean, how much ethanol can an acre of corn waste (or grass, or whatever other plant material you are using) compare to the energy output of an acre of 20% efficient solar panels?

The trouble is portable fuel. Batteries and fuel cells just don't have the energy density (energy per unit mass) of liquid fuels. So for the foreseeable future we need long haul trucks and airplanes driving on liquids if not necessarily your commuter car.

Forget the byproducts of agriculture, those already have uses lets start growing bamboo on "waste" land and use treated water from cities to water it. Then build the facilities to do the conversion near the fields of bamboo so you don't have to transport it vary far. And if you do a really good job of picking the location you could even have wind & solar to offset the energy used in the processing...Now where to find such an ideal location: How about between San Antonio & El Paso in the "bad lands"?Waste land: checkAble to get treated waste water from cites: Check (with some piping)Empty space to build facilities: CheckAble to use solar & wind at site: CheckAnd near a major interstate highway as well!

It all sounds good to me, although I do wonder what effect planting thousands of acres of bamboo (& watering it) in this desert(ish) area would have an impact on the climate in the area.

This is some pretty neat tech, but wouldn't it be more efficient to skip a step and capture the solar energy ourselves, rather than letting plants do it? I mean, how much ethanol can an acre of corn waste (or grass, or whatever other plant material you are using) compare to the energy output of an acre of 20% efficient solar panels?

The trouble is portable fuel. Batteries and fuel cells just don't have the energy density (energy per unit mass) of liquid fuels. So for the foreseeable future we need long haul trucks and airplanes driving on liquids if not necessarily your commuter car.

Umm.. fuel cells run on liquid fuels.

While fuel cells can be run on liquid hydrocarbons most run best on pure gas or liquid hydrogen which can be produced straight from electricity (and water). It's the hydrocarbons that cannot be converted straight from electricity.

However, your comment it not incorrect.

Edit: and liquid fueled or not I haven't seen a total fuel cell system (including heaters, tanks, etc.) that can compete with a diesel engine or gas turbine for power and/or energy density including fuel tanks.